Interpretive Summary: Beef feedlot operations are concentrated in the Central and Southern Great Plains. On an annual basis the manure excreted by these animals contains approximately 530 000 Mg of N. If used properly, manure N could meet the fertilizer needs of nearly 10% of the wheat and corn acreage in the U.S. Efficient use of the manure resource requires improved understanding of the rate that nutrients become available to the crop. A laboratory study was conducted that compared the release of N in a sandy loam, a loam, and a clay loam soil at either a constant, 60% water-filled pore space, or a repeated wet-dry cycle, from 60 to 30% water-filled pore space. The study was conducted at four temperatures ranging from 11 to 32 C. The study was conducted using a standardized protocol, being used by several labs across the country, so that the results can be combined into a national database and used to develop robust models for estimating nutrient availability in manure amended soils.

Technical Abstract:
Beef feedlot operations are concentrated in the Central and Southern Great Plains. On an annual basis the manure excreted by these animals contains approximately 530 000 Mg of N. If used properly, manure N could meet the fertilizer needs of nearly 10% of the wheat and corn acreage in the U.S. Efficient use of the manure resource requires improved understanding of the rate that nutrients become available to the crop. A laboratory study was conducted that compared the release of N in a sandy loam, a loam, and a clay loam soil at either a constant, 60% water-filled pore space, or a repeated wet-dry cycle, from 60 to 30% water-filled pore space. The study was conducted at four temperatures ranging from 11 to 32 C. The study was conducted using a standardized protocol, being used by several labs across the country, so that the results can be combined into a national database and used to develop robust models for estimating nutrient availability in manure amended soils.